Load-lifting jack



v Nov. 19, 1929. AN. G; |V ARsoN LOAD LIFTING Jacx Filed Dec. 21. 1928 INVEN TOR.

BY @www lPatented Nov. 19,- 19.29

' -lumrED STA NILS e. LAnsoN, oFATTLEBono, MASSACHUSETTS, AssiGNon To so-Lo :rAcx co., nic..

or ATTLEEono, MASSACHUSETTS, A conroaATIoN or mASsAcHUsETTs LoAD-LIFTING .Tacx

Application. led December 21, 1928. Serial No. 827,671. Y* Q l This invention relates to an improved construction of lifting jack, which simulates the so-called lazy tongs construction in its opening and closin actions, the same being more particularl a apted to be positioned beneath the axle o an automobile to lift the same; and this invention is an improvement on the patent numbered 1,612,447, dated December 28, 1926, andassigned to the assignee of the present invention; land the object of the present invention is to provide ajack of this character which is adapted to be contracted to a very low position so that it may be readily inserted under the axle of a vehicle when one or both of the tires are deflated, which is particularly necessary where the vehicle has the so-called balloon type of-tire, which permits the axle to drop very close to the ground. t

A further object of the invention is to provide anA improved construction of lazy tongs type of jack wherein the arms of the jack 'are so shaped and the screw is so positioned on these arms that the arms afford protection to the ends of the screw to revent the same from bein bent when the jac tips over which is often t e case while being positioned beneath the axle and withdrawn from such position. i, f

' The invention further consists in the pivscrew-receiving nutsl otin of the operatin on tiie arms of the jac at a point to one side ofa center line thru the end pivots of the arm and in such position that a center line thru 'the' nut .pivot at right angles to said l line thru the endpivots, will intersect this end pivot center line at a point intermediate said end pivots, by which construction the end portions of the armsfbetween which the` operating screwis mounted serve as an effective protection for the ends of the screw to bent outV of ling of the jack upon .extended stroke.

TES PATENT oEFIcE of construction, as will be more fully' described, and particularly pointed out in the 1 ap ended claims.

n the laccompanying drawings:

Fig. 1 shows my improved ]ac in collapsed@ l.

or contracted position.

Fig. 2 is atop viewof the shown in the positionlillustrated in Fi 1.

. 5 F1g.3is a sectional elevation online 34e-3 of Fig. 2.

Fig. 4 shows the 'j ack as being in raised or extended position a -1ittleshort of its extrema Fig. 5 is an enlarged view 'thru the ivot screw receiving nut, on line `5 5 of Fig. 2, showing the stock in the arms as being recessed to receive-the heads of the nut pivots so as not to interfere with the outside set of arms while vworking close to the surface of the.l inside arms.

l It has been found in another type of jack vof the lazy tongs construction where the screw-operating nuts are pivoted at points beyond and not intermediate the end pivot points of the arms that when the jack is in raised or paritiall ,raised position a considerable portion o the ends of the operating- Screw pro'ect and are exposed beyond the parts of t e jack so that when the jack is tipped over as is often the case in v eneraluse while being manipulated beneath t e axle of the vehicle the screw ends rare 'often bent rendering the jack inoperative, and toobviate this diiiiculty in a simple.`and eective way, I have so positionedthe pivot points of the operating nuts in the arms of the jack that\ portions of these arms, to some extent in all positions of the jack, extend'out beyond the nuts at a point intermediate the end pivots a quick operating action to the jack ,is propairs and the arms of each The upper set of arms 14 comprise two air are spaced vfrom each otherand are -pivoted. las at 15 at one end to the load rest The opposlte ends of these arms arebffset as at 17- to eX- tend outwardly in opposite dire'c'tions and .the outer ends of these arms are pivoted as at 18 to the corresponding free ends of the set of arms 10.

These upper arms 14 are also provided at their ends withintermeshing 4teeth 19 lwhich cause .them to mover in unison. On each of these offset arms I have pivoted at 20 a screwreceiving Vnut 21, which is provided with laterally-extending trunnions 22. having up-A set 'ends to nestin the recesses formed in its arm-"14.

These nuts 21 'are pivoted at each end in its arms 14 at a point to one side of a center line 24 passing thru the centers of the 'end pivots 15 and-18 and in suchI position that a center line .25, 4see Fig. 4, thru the nut pivot 20 and set at a` right anglevto the line 24 will intersect said line 24 at a point-intermediate its end pivots 15'and 18. i

The operating screw 27 that engages these nuts 21 is located in the space between the arms; and has right and left hand threaded portions which respectively engage these nuts'and one end of the screw is fiattened or formed square as at 28 to receive the operating wrench (not shown) By so locating these screw-operated nuts y in which the screwis mounted the outwardlyturned portions 17 of the arms 1'4 serve as a convenient guard for thev effective protection of the end portions 26 .of the screw and insures them against being bent while the .jack

l is being mampulated.

My improved jack is preferably formed of sheet stock and is therefore Very light in weight and at the same time is very strong and durable. The jack is also very simple and practical inconstruction and is effective in its operation and by itsconstruction may be collapsed or lowered to a minimum height and yet bequickly manipulated toA lift a heavy load. v

The foregoing description is directed soletowards the construction illustrated, but I i 1 diesirc it to bel understood that I reserve 'the privilege of resorting to all the mechanical changes-towhich the device is susce tible, the invention being defined and limite only -by the terms of the appended claims.

I claim:

`1. A load lifting jack' comprising a basek member, a set of arms pivoted at one end to opposite sides of said base,` a load'rest, aset o f arms pivoted at one end'to opposite sides of said rest, theJ free ends of said different sets being pivoted together, nut members pivoted to the arms of one of said sets at a pointin each arm to one side of a center line thru the end pivots. of the arm and insuch position that a center line thru thel nut pivot at right angles to said line thru the end pivots will intersect said end pivot center line at a point intermediate said end pivots, anda right and left hand operating screw in said nuts to move-the load rest towards andfrom 'its base member. j

2. A load lifting jack comprising a base p member, a set of arms .pivoted at one, endto said base, a load rest, a set of arms pitfoted at one end to said rest, the opposite ends-of saidv sets being pivoted toget er, the opposite arms of one set having'outturned oppositely extending end portions of a substantial length, a nut member pivoted to each of said arms at the bend of its angle and positioned intermediate the opposite -ivotends of said arms, and aright and le t hand operating screwj threaded thru said nut members toV move the load rest towards and from its base, whereby the outturned portions of said arms serve as a guard for the opposite end portions 'of the operatin screw.

3. A load li" ing jack comprising a base member, a set of arms pivoted at one end to said base, a load rest, a setof arms pivoted at one end to said rest, said sets being piv.

ote'd together at their free ends the arms of one of said sets each having a body portion and a screw protecting outturned end portion of substantial length, the centre lines thru the ivotbpoints of said body and said outturne end portions being set at an obtuse angley to each other, a nut member pivoted to i each yof said arms substantially at the inter A section of said twocenter lines, and a right and left hand operating screw engaging said nuts to move'the load rest towards and from itsbase member.

4. A load lifting jack comprising a base member, a set'of arms comprising two spaced pairs, said pairs being pivoted at one end to opposite sides ofsaid base, a load rest, a set of arms comprising two spaced pairs, said pairs being pivoted at oneend 'tovopposite arm, and in such position that a center line l thru the nut pivot at right angles to line thru the end pivots, w111 intersect 'said end pivot eenter line at a point intermediate its pivots, the arms in which said nuts are Y ivoted'heing recessed,'the ends of said pivot trunnions on said nuts being enlarged in said recesses to set below the outer surface of its arm', and a right and left hand screw in said nuts to move the load rest towards and from its base member.

In testimony whereof I aiiix my signature.V

NILS G. LARSON. 

